CN110215759B

CN110215759B - Filter apparatus and method of filtering fluid used in semiconductor manufacturing

Info

Publication number: CN110215759B
Application number: CN201810174853.5A
Authority: CN
Inventors: 王建惟; 张庆裕; 赖韦翰; 林进祥
Original assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
Current assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
Priority date: 2018-03-02
Filing date: 2018-03-02
Publication date: 2022-05-03
Anticipated expiration: 2038-03-02
Also published as: CN110215759A

Abstract

The present disclosure provides a filter device, which includes a housing, a filter element, and an electric field generating unit. The housing has an inlet and an outlet, wherein the inlet allows a fluid to flow into the housing and the outlet allows the fluid to flow out of the housing. The filter element is disposed between the inlet and the outlet for filtering impurities in the fluid flowing through the filter element by an adsorption method. The electric field generating unit is configured to generate an electric field so that the impurities move to the filter element along the direction of the electric field.

Description

Filter apparatus and method of filtering fluid used in semiconductor manufacturing

Technical Field

The present disclosure relates to semiconductor technology, and more particularly, to a filtering apparatus and a filtering method for filtering various fluids used in semiconductor manufacturing.

Background

Semiconductor devices are used in a variety of electronic applications such as personal computers, cellular phones, digital cameras, and other electronic devices. The fabrication of semiconductor devices typically involves a number of processing steps, including photolithography, etching, ion implantation, doping, annealing, and packaging (hereinafter referred to as "processes"). In these processes, various different types of fluids or chemicals may be used, including, for example, water, photoresist, developer, etchant, slurry, process or cleaning gases, and the like. These fluids are typically filtered before being delivered to a semiconductor manufacturing facility for use.

Although the existing filtration systems and filtration methods have been adequate to meet the needs, they have not been fully satisfactory. Therefore, it is desirable to provide a solution that can improve the effectiveness of filtering impurities in a fluid.

Disclosure of Invention

Some embodiments of the present disclosure provide a filter device, which includes a housing, a filter element, and an electric field generating unit. The housing has an inlet and an outlet, wherein the inlet allows a fluid to flow into the housing and the outlet allows the fluid to flow out of the housing. The filter element is arranged between the inlet and the outlet and is used for filtering impurities in the fluid flowing through the filter element in an adsorption mode. The electric field generating unit is configured to generate an electric field so that the impurities move to the filter element along the direction of the electric field.

Some embodiments of the present disclosure provide a filter device including a housing, a filter element, an electric field generating unit, and an electrode mounting mechanism. The housing is configured to allow a fluid to flow in and out. The filter element is arranged on the flowing route of the fluid in the shell and is used for filtering impurities in the fluid in an adsorption mode. The electric field generating unit is configured to generate an electric field so that the impurities move to the filter element along the direction of the electric field, wherein the electric field generating unit comprises a first electrode, a second electrode, and a power source for generating the electric field between the first electrode and the second electrode. The electrode mounting mechanism is configured to mount the first electrode and the second electrode to the housing.

Some embodiments of the present disclosure provide a method of filtering a fluid used in semiconductor manufacturing, including flowing a fluid through a filter element. The filtering method further comprises generating an electric field so that impurities in the fluid move onto the filter element along the direction of the electric field. Further, the filtering method includes adsorbing the aforementioned impurities by a filter element to filter the fluid.

Drawings

FIG. 1 shows a schematic diagram of a filtration system according to some embodiments.

Fig. 2A shows a schematic cross-sectional view of the filter apparatus (14) of fig. 1, according to some embodiments.

Fig. 2B shows a partial perspective view of the filter element of fig. 2A.

Fig. 2C shows a schematic view of a filter element that may not be parallel to the cover and bottom wall of the tank of the filter device, according to some embodiments.

Fig. 3A, 3B show schematic cross-sectional views of the filter apparatus (14) of fig. 1, according to some embodiments.

Fig. 4 shows a schematic cross-sectional view of the filter device (15) of fig. 1, according to some embodiments.

Fig. 5 shows a schematic view of a portion of impurities in a fluid that may be adsorbed by a filter element.

Fig. 6 shows a schematic diagram of a filter device further comprising an electric field generating unit according to some embodiments.

Fig. 7 shows a schematic diagram of the swing behavior of the impurities in the fluid under the action of the ac electric field.

FIG. 8 is a schematic diagram of an electric field generating unit with electrodes not parallel to a filter element according to some embodiments.

Fig. 9 shows a schematic view of electrodes of an electric field generating unit disposed in a housing, according to some embodiments.

FIG. 10 is a schematic diagram of another arrangement of electrodes of an electric field generating unit according to some embodiments.

Fig. 11 shows a flow diagram of a method of filtering a fluid used in semiconductor manufacturing, in accordance with some embodiments.

Description of reference numerals:

10-a filtration system;

11-a storage tank;

12-a semiconductor manufacturing machine;

13-pipeline system;

14-a filtering device;

15-a filtering device;

140-shell;

141-groove body;

141A-side wall;

141B-bottom wall;

142-cover body;

142A-inlet;

142B-an outlet;

142C-exhaust port;

143-a filter element;

143A to open a hole;

143B to the surface;

143C to the surface;

150 to the shell;

151-groove body;

152-cover body;

152A to an inlet;

152B to an outlet;

153-a filter element;

153A-opening a hole;

153B-surface;

153C-surface;

154-electric field generating unit;

1541-a first electrode;

1542-a second electrode;

1543-power supply;

155 to a bracket;

156-a partition plate;

200-filtering method;

201-203-operation;

c-fluid;

e, electric field;

p1-part/first part/outside part;

p2-part/second part/inside part;

p1 ', P2' Compartment;

x1, X2, X3-impurities;

alpha-angle.

Detailed Description

The following disclosure provides many different embodiments, or preferred examples, for implementing different features of the disclosure. Of course, the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The following detailed description of specific examples of components and arrangements thereof, taken in conjunction with the accompanying drawings, is provided to simplify the description and to provide a more complete and thorough understanding of the disclosure and to fully convey the scope of the disclosure to those skilled in the art.

Spatially relative terms, such as "below," "lower," "above," "upper," and the like, may be used hereinafter with respect to elements or features in the figures to facilitate describing a relationship between one element or feature and another element(s) or feature(s) in the figures. These spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be oriented in different orientations (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It is to be understood that elements not specifically shown or described may exist in various forms well known to those skilled in the art. In addition, if the embodiments describe a first feature formed over or on a second feature, that is, the description may include the first feature being in direct contact with the second feature, or additional features may be formed between the first and second features, such that the first and second features are not in direct contact.

The same reference numbers and/or letters may be repeated in the various embodiments below for simplicity and clarity and are not intended to limit the particular relationship between the various embodiments and/or structures discussed. In the drawings, the shape or thickness of the structures may be exaggerated to simplify or facilitate labeling.

FIG. 1 shows a schematic view of a filtration system 10 according to some embodiments of the present disclosure. The filtration system 10 may be used to filter various fluids C (or chemicals) used in multiple processes of semiconductor manufacturing, including, for example, water, photoresist, developer, etchant, slurry, process or cleaning gases, and the like.

As shown in FIG. 1, the filtration system 10 includes a reservoir 11 for providing storage and protection functions before the fluid C is delivered to a semiconductor fabrication tool 12 for manufacturing use. In some embodiments, the semiconductor fabrication tool 12 may be a chemical vapor deposition tool, a physical vapor deposition tool, an etching tool, a thermal oxidizer tool, an ion implantation tool, a chemical mechanical polishing tool, a rapid thermal anneal tool, a photolithography tool, a diffusion tool, or a semiconductor fabrication tool that performs other types of processes.

Depending on the properties of the stored fluid C, the reservoir 11 may be made of any suitable material to avoid, for example, the material of the reservoir 11 reacting with the fluid C to cause deterioration or contamination of the fluid C. For example, when the fluid C is a Negative Tone Developer (NTD), the storage tank 11 may be made of a material that does not contain Polyethylene (PE) or high density polyethylene, such as Polytetrafluoroethylene (PTFE) or Polyfluoroalkyl (PFA), so as to prevent the negative tone developer from being contaminated by the PE. However, when the fluid C is water or deionized water, the storage tank 11 may also be made of plastic material such as polyethylene, so as to reduce the material cost.

Furthermore, the fluid C stored in the storage tank 11 may be delivered to the semiconductor manufacturing tool 12 through a series of piping systems 13 before the semiconductor manufacturing tool 12 starts to perform the process. In some embodiments, piping system 13 includes piping, pumps, valves, and flow meters to deliver fluid C to semiconductor fabrication tool 12 at a predetermined flow rate for a predetermined period of time. The operation of the piping system 13 may be controlled by a control system (not shown), which may be a stand-alone computer control system or a process control system coupled to the semiconductor fabrication tool 12.

In some embodiments, as shown in fig. 1, a plurality of

filtering devices

14 and 15 are disposed in the piping system 13 for filtering impurities in the fluid C (e.g., particles, metal ions, or other foreign substances that may be doped during the preparation or transportation of the fluid C) to prevent the impurities from affecting or damaging the process results of the subsequent semiconductor manufacturing tool 12 (e.g., the impurities may scratch the surface of the wafer processed in the semiconductor manufacturing tool 12).

Referring to fig. 2A, a cross-sectional view of the filter 14 of fig. 1 according to some embodiments is shown. The filtering device 14 includes a housing 140 including a tank 141 for receiving a fluid C (fig. 1) to be filtered and a cover 142 for closing the tank 141. The groove 141 may be designed in any shape suitable for receiving the fluid C and carrying a filter element 143 to be described later. In some embodiments, the trough 141 includes a cylindrical sidewall 141A and a bottom wall 141B connected to the sidewall 141A, wherein a space for containing the fluid C is formed between the sidewall 141A and the bottom wall 141B. In other embodiments, the slot 141 may have other suitable shapes, such as a hollow square, hexagon, octagon, or other polygon.

The tank 141 may be made of a material that does not react with the fluid C to be filtered and can withstand the pressure of the fluid. In some embodiments, the material of the channel 141 includes stainless steel, nickel, aluminum, alloys of the above metals, or other suitable metals or alloys. In other embodiments, in order to prevent the metal material or ions from contaminating the fluid C to be filtered and affecting the subsequent semiconductor process, a protection layer, such as teflon (teflon), may be further formed inside the tank 141. Alternatively, the material of the tank 141 may be selected from other suitable plastic materials (e.g., polyethylene) or insulating materials (e.g., teflon), depending on the characteristics of the fluid C to be filtered. The cover 142 is generally made of the same or similar material as the tank 141.

In some embodiments, the cover 142 may be attached to the tank 141 by, for example, an O-ring, gasket, or other optional seal (not shown), thereby preventing leakage of the fluid C in the tank 141 while allowing the cover 142 to be removed from the tank 141 to allow for disposal of the interior of the tank 141 (e.g., loading the filter element 143 into the tank 141). Alternatively, the cover 142 may be integrally formed with the groove 141 by a connection method such as welding or adhesion, thereby achieving airtight sealing and effectively preventing the fluid C from leaking.

In some embodiments, as shown in fig. 2A, the cover 142 may have an inlet 142A and an outlet 142B formed thereon for allowing a fluid C to be filtered to flow into the housing 140 and allowing a filtered fluid C (i.e., the filter element 143) to flow out of the housing 140 (as indicated by directional arrows). Alternatively, the inlet 142A and the outlet 142B may be formed on the side wall 141A and/or the bottom wall 141B of the tank 141, respectively. In addition, the inlet 142A and outlet 142B may be provided with various optional valves or pipe connections (not shown) to facilitate removal or replacement of the filter apparatus 14 (in the piping system 13).

Referring to fig. 2A and 2B, a filter element 143, such as a membrane with a porous structure, is installed in the housing 140 of the filter device 1 (fig. 2B). The filter element 143 may be disposed between the inlet 142A and the outlet 142B and divide the interior of the housing 140 into two generally symmetrical portions P1 and P2. In some embodiments, the filter element 143 can be perpendicular to the bottom walls of the cover 142 and the trough 141 (fig. 2A). Inlet 142A is connected to first portion P1 and outlet 142B is connected to second portion P2, whereby fluid C entering housing 140 from inlet 142A needs to flow through filter element 143 (as indicated by the directional arrows in the figure) before exiting housing 140 from the outlet, so that it can be filtered by filter element 143. In other embodiments, the filter element 143 may not be perpendicular to the bottom walls of the cover 142 and the trough 141 (as shown in fig. 2C).

In addition, the filter element 143 may have various other structural configurations as long as it is disposed on the flow path of the fluid C in the housing 140. For example, fig. 3A shows that in some embodiments, the filter element 143 (porous membrane) can also be configured to connect to the cover 142 and divide the interior of the housing 140 into an inner portion P2 and an outer portion P1 (the filter element 143 is generally rectangular when viewed in cross-section) surrounding the inner portion P2, wherein the outer portion P1 connects to the inlet 142A and the inner portion P2 connects to the outlet 142B. In this way, the fluid C entering the housing 140 from the inlet 142A may also need to flow through the filter element 143 (as indicated by the directional arrow in the figure) before exiting the housing 140 from the outlet, so as to be filtered by the filter element 143. In other embodiments, the positions of inlet 142A and outlet 142B may be reversed such that inner portion P2 connects with inlet 142A and outer portion P1 connects with outlet 142B. In other embodiments, the filter element 143 may also have a generally trapezoidal shape when viewed in cross-section (as shown in FIG. 3B).

In the embodiment of fig. 3A, 3B, a vent 142C is also formed in the cover 142 of the filter apparatus 14 and is operable to controllably (e.g., by the aforementioned control system) vent gases that may be generated during maintenance or other emergency of the filter apparatus 14 to controllably relieve pressure that may build up in the filter apparatus 14. In addition, to facilitate installation or operation of the exhaust port 142C, the exhaust port 142C may also be provided with various optional valves or pipe connections (not shown).

As shown in fig. 2B, the filter element (membrane) 143 has a plurality of openings 143A (through opposing

surfaces

143B, 143C of the filter element 143) for allowing fluid C to flow through the filter element 143 (as indicated by the directional arrows in the figure). Meanwhile, the opening 143A may serve as a filtering mechanism for preventing impurities in the fluid C having a size larger than that of the opening 143A from passing through the filter element 143. It should be appreciated that the size of the opening 143A is at least partially dependent upon the type of process performed by the semiconductor fabrication tool 12 and the type of fluid C to be filtered by the filter apparatus 14 (and the filter element 143). For example, the size of the opening 143A is generally dependent on the size of the contaminants in the fluid C desired to be filtered out, while other factors, such as the pressure drop (pressure drop) of the fluid that may pass through the filter apparatus 14, must also be considered. In some embodiments, the cross-sectional shape of the opening 143A may be circular, triangular, square, octagonal, or other polygonal shapes.

The filter element 143 may be made of a material that is chemically inert to the fluid C to be filtered, so as to avoid the fluid C from reacting with the filter element 143 during the filtering process and causing a change in properties. In some embodiments, the material of the filter element 143 may include a non-polar polymer, such as ultra-high molecular weight polyethylene (UPE), polytetrafluoroethylene (ptfe), or other similarly structured non-polar polymer. Thereby, the ability of the filter element 143 to filter impurities of a particular size may be physically (or structurally) controlled by the size of the openings 143A.

Referring next to fig. 1 and 4 together, fig. 4 is a cross-sectional view of the filter device 15 of fig. 1 according to some embodiments. After the fluid C is filtered by the filtering device 14, it may be sent to a filtering device 15 to further filter smaller impurities from the fluid C. It should be understood that the filter device 15 includes a housing 150 including a tank 151 for receiving the fluid C (fig. 1) to be filtered and a cover 152 for closing the tank 151. The cover 152 may be formed with an inlet 152A and an outlet 152B for allowing a fluid C to be filtered to flow into the housing 150 and a fluid C filtered (a filter element 153 to be described later) to flow out of the housing 150, respectively (as indicated by directional arrows in fig. 4). The inlet 152A of the cover 152 may be connected to the outlet 142B of the filter apparatus 14 by a pipe. The housing 150, the tank 151, the cover 152, the inlet 152A, and the outlet 152B of the filtering device 15 are similar to the housing 140, the tank 141, the cover 142, the inlet 142A, and the outlet 142B of the filtering device 14 in the above-mentioned design (including structural configuration and materials), and thus, the description thereof is not repeated herein. However, in other embodiments, the filter device 15 may be designed differently from the filter device 14 (e.g., the two filter devices are designed as shown in fig. 2A and 3, respectively).

As shown in fig. 4, the housing 150 of the filter device 15 is provided with a filter element 153, such as a membrane having a porous structure. Similar to the filter element 143 of the filter apparatus 14 described above, the filter element 153 has a plurality of openings 153 (shown in phantom lines through opposing

surfaces

153B, 153C of the filter element 153) operable to allow the fluid C to flow through the filter element 153 and to prevent impurities in the fluid C that are larger in size than the openings 153A from passing through the filter element 153 (i.e., impurities of different sizes can be filtered by adjusting the size of the openings 153A). One difference between the filter element 153 and the filter element 143 (fig. 2A and 2B) is that the size of the opening 153A of the filter element 153 is smaller than the size of the opening 143A of the filter element 143, so as to filter out smaller impurities in the fluid C, which may affect the process result of the subsequent semiconductor manufacturing tool 12.

In other embodiments, it is also possible to provide only the filter device 15 in the filter system 10 and to omit the filter device 14.

Although the above embodiments illustrate the structural features of the

filter elements

143, 153 as an example of a membrane, other structures with open pores (such as a metal or ceramic sintered mesh structure or a porous columnar structure) may be used as the

filter elements

143, 153.

Further, in order to improve the filtering capability of the filtering element 153, the material may be a polar polymer (polar polymer) that does not contaminate the fluid C to be filtered, such as nylon or other similar polar polymers, so as to adsorb polar impurities or non-polar impurities in the fluid C (which are not expected to reach the semiconductor manufacturing tool 12). It is understood that "adsorption" as used herein includes "physisorption" and "chemisorption" (both adsorption mechanisms may act independently or simultaneously), which are well known to those skilled in the art, wherein "chemisorption" (also referred to as "active adsorption") refers to chemical bonds (bonding) such as ionic, covalent, or metallic bonds, when adsorption is used, and "physisorption" refers to physical bonds in a broad sense such as Van der waals force (Van der waals force) or electrostatic attraction, when adsorption is used, when the forces between molecules are used.

Referring to fig. 5, a schematic diagram of a part of the impurities X1 in the fluid C being adsorbed by the filter element 153 is shown. As shown in fig. 5, the polar or non-polar impurities in the fluid C are adsorbed by the filter element 153 and filtered on the premise that the impurities X1 must contact the filter element 153 or be very close to the filter element 153 (so that there is an opportunity for chemical or physical bonding with the filter element 153), and the impurities X2 in the fluid C moving along with the fluid C (as shown by the directional arrow) and not contacting or spaced from the filter element 153 cannot be effectively adsorbed by the filter element 153 and removed. Therefore, in order to increase the chance of the impurities in the fluid C moving to the filter element 153 and further improve the ability of the filter device 15 to filter the impurities by adsorption, the following technical means are proposed in some embodiments of the present disclosure.

Referring to fig. 6, in some embodiments, the filter device 15 (in addition to the elements described in fig. 4) further includes an electric field generating unit 154 including a first electrode 1541, a second electrode 1542, and a power source 1543. First electrode 1541 and second electrode 1542 are, for example, two planar electrode plates made of conductive material (e.g., metal) respectively disposed on opposite sides of filter element 153, e.g., first electrode 1541 may be disposed on one side of filter element 153 near inlet 152A, and second electrode 1542 may be disposed on the other side of filter element 153 near outlet 152B. The power source 1543 is configured to apply a corresponding (dc or ac) voltage to the first electrode 1541 and the second electrode 1542, and generate a (dc or ac) electric field E therebetween. In the embodiment of fig. 6, in order to avoid the influence of the shielding effect (shielding effect) on the electric field E, the housing 150 may be made of other suitable materials besides metal.

In some embodiments, the housing 150 of the filter device 15 also has a plurality of extending supports 155 (electrode mounting mechanisms) on the outside thereof for mounting and positioning the first electrode 1541 and the second electrode 1542, respectively, on the housing 150. In the embodiment of fig. 6, support 155 may position first electrode 1541 and second electrode 1542 substantially parallel to filter element 153. The support 155 may include any suitable mechanism for clamping, locking, or otherwise adhering the first electrode 1541 and the second electrode 1542 (e.g., the support 155 in the embodiment of fig. 6 includes a clamping mechanism that can clamp the edges of the electrodes to achieve a secure attachment). In addition, the bracket 155 may use the same or different material as the housing.

With the above configuration, impurities to be filtered in the fluid C (fig. 1) passing through the filtering device 15 (under the action of the electric field E) can move onto the filtering element 153 along the direction of the electric field E (as indicated by the directional arrow in the figure). In more detail, when the power source 1543 provides a dc voltage (as shown in fig. 6), a dc electric field E may be generated between the first electrode 1541 and the second electrode 1542, so that the impurity X3 to be filtered in the fluid C (under the action of the electric field E) may uniformly move to the surface 153B of the filter element 153 (near the inlet 152A) along the direction of the electric field E and be adsorbed by the surface 153B. In some embodiments, the electric field direction of the dc electric field E is substantially perpendicular to the filter element 153. When the power source 1543 provides an ac voltage (as shown in fig. 7), an ac electric field may be generated between the first electrode 1541 and the second electrode 1542, and the direction of the electric field may change (for example, exhibit a sinusoidal waveform) with time, so that the impurity X3 to be filtered in the fluid C (under the action of the electric field E) may swing along the direction of the electric field E to extend the time of passing through the filter element 153, thereby increasing the probability that the impurity X3 contacts with the filter element 153 and is adsorbed by the filter element 153.

The impurities in the fluid C can only move to the filter element 153 by random diffusion (diffusion limit is relatively small) relative to the situation where no electric field is applied. Therefore, the filtering device 15 in this embodiment can drive the impurities X3 to be filtered in the fluid C to move in a directional manner by the force of the electric field E (at the same time, the diffusion limit of the impurities X3 can be increased), and the chance that the impurities X3 move to the filtering element 153 or contact the filtering element 153 is increased, so that the capability of the filtering device 15 to filter the impurities by using an adsorption manner can be improved.

It should be appreciated that the electric field is used for overcoming the energy barrier that the impurity X3 to be filtered needs to cross when diffusing and adsorbing to the filter element 153, so as to improve the adsorption efficiency, and the terms of the similar relations include, for example, diffusion limit reaction (diffusion limit adsorption) or diffusion limit adsorption (diffusion limit adsorption). This effect is more pronounced when the concentration of the impurity X3 to be filtered is very low, thereby effectively avoiding the occurrence of defects (defects) in the subsequent process caused by the undesired impurity on the semiconductor manufacturing machine 12 side. In a typical semiconductor process, the defect rate is desirably controlled to be less than about 1 to 100counts/12inch wafer.

In some embodiments, the magnitude and/or frequency of the voltage provided by the power source 1543 can be controlled and adjusted according to different characteristics of the impurities (polar or non-polar) to be filtered in the fluid C, so as to generate a corresponding and sufficient electric field E force to drive the impurities. For example, when the impurities to be filtered are polar impurities, the power supply 1543 may be controlled (e.g., by human or computer control) to provide a lower voltage, such as dc or ac voltage, and to drive the impurities by the electrostatic attraction between the generated electric field E and the polar impurities. On the other hand, when the impurities to be filtered are nonpolar impurities, the power supply 1543 may be controlled to provide a dc or ac voltage of a relatively high voltage, and the impurities may be driven by induced dipole forces between the generated electric field E and the nonpolar impurities. In some embodiments, the voltage provided by power supply 1543 ranges from 0.5V (volts) to 1000V, and the frequency of the voltage provided by power supply 1543 ranges from 0Hz (Hertz) to 100 KHz.

In addition, the magnitude of the voltage provided by the power source 1543 can be adjusted according to the magnitude of the impurity to be filtered. For example, when the impurities to be filtered have a larger size, the power source 1543 may provide a higher voltage to generate a sufficient force of the electric field E to drive the impurities. Conversely, when the impurity to be filtered has a smaller size, the power supply 1543 may only provide a lower voltage to reduce energy consumption.

In addition, the power source 1543 may provide voltage in a continuous or discontinuous manner to generate a continuous or discontinuous electric field according to the difficulty of driving the impurities to be filtered by the force of the electric field E. For example, when the impurities to be filtered are non-polar impurities and/or have a large size, the power source 1543 can continuously provide a high voltage dc or ac voltage during the passage of the fluid C through the filtering device 15 to generate a continuous and sufficient electric field E to drive the impurities to move onto the filtering element 153. Conversely, when the contaminants to be filtered are polar contaminants and/or have a relatively small size, the power source 1543 may provide a relatively low dc or ac voltage non-continuously (i.e., intermittently) during the passage of the fluid C through the filter device 15, which may also generate an electric field E force sufficient to drive the contaminants.

It should also be appreciated that the difference between the embodiments of the present disclosure using electric field to improve the filtering efficiency of the filtering element 153 and the traditional capillary electrophoresis separation technique includes that the capillary electrophoresis separation technique does not use the filtering element 153 (filtering membrane), but directly uses the force of the electric field to generate different moving rates of the charged particles with different sizes in the fluid to achieve the separation effect, so that a relatively large electric field (for example, the applied voltage is at least greater than 20KV) needs to be applied. In contrast, the electric field used in the embodiment of the present invention is mainly used to increase the chance of diffusing and adsorbing the impurity X3 to be filtered to the filter element 153, and therefore, the voltage can be relatively lower than the high voltage used in capillary electrophoresis. In addition, capillary electrophoresis is only suitable for micro-separation (e.g., μ L), and the filtering device 15 of the embodiment of the present disclosure can be used to filter a larger amount of fluid (e.g., greater than 1L).

Many other variations and modifications are possible in the embodiments of the disclosure. For example, fig. 8 shows that according to some embodiments, the bracket 155 outside the housing 150 may be adjusted and the first electrode 1541 and the second electrode 1542 of the electric field generating unit 154 are disposed not parallel to the filter element 153, such that the direction of the (e.g., direct current) electric field E generated by the electric field generating unit 154 may form an included angle α with the surface 153B of the filter element 153, which is between 0 degree and 180 degrees (but does not include 0 degree, 90 degrees, and 180 degrees), for example, the included angle α is 45 degrees. In this way, compared to the case that the direction of the electric field E is substantially perpendicular to the filter element 153 (i.e., the first electrode 1541 and the second electrode 1542 are substantially parallel to the filter element 153), in addition to the impurities X3 to be filtered in the fluid C still moving onto the filter element 153 along the direction of the electric field E, the chance that the impurities X3 easily pass through the opening 153A of the filter element 153 can be reduced (incidence in an oblique manner can increase the chance that the impurities X3 contact the sidewall of the opening 153A), so as to improve the ability of the filter device 15 to filter the impurities by adsorption.

Fig. 9 shows that the first electrode 1541 and the second electrode 1542 of the electric field generating unit 154 can also be disposed in the housing 150 according to some embodiments. As shown in fig. 9, the first electrode 1541 and the second electrode 1542 may be disposed in compartments P1 'and P2' further partitioned by the partition 156 in the housing 150, respectively, and when the cover 152 is connected to the tank 151, the compartments P1 'and P2' are not communicated with other spaces in the housing 150, thereby preventing the first electrode 1541 and the second electrode 1542 from contacting the fluid C to be filtered to contaminate the fluid C or deteriorate the fluid C. The power source 1543 of the electric field generating unit 154 may pass through a wiring opening (not shown) on the cover 152 via a wire to provide a voltage to the first electrode 1541 and the second electrode 1542.

In the embodiment of fig. 9, the spacer 156 may be made of other suitable material than metal to prevent the electric field E from being affected by the metal shielding effect. In some embodiments, if the fluid C to be filtered is not suspected to be contaminated by metal materials or ions, the first electrode 1541 and the second electrode 1542 may be disposed directly in the housing 150 (disposed in the first portion P1 and the second portion P2, respectively), and the partition 156 may be omitted. In addition, although not explicitly shown in fig. 9, compartments P1 'and P2' may be designed with sufficient space and/or with positioning structures to allow first electrode 1541 and second electrode 1542 to be disposed non-parallel to filter element 153 or at an appropriate angle to filter element 153.

Fig. 10 shows that according to some embodiments, the filter device 15 may have a similar structural design as the filter device 14 in fig. 3. In addition, an electrode (e.g., the first electrode 1541, which is a bar-shaped or rod-shaped electrode) of the electric field generating unit 154 may be disposed in the inner portion P2 in the housing 150 (i.e., the filter element 153 surrounds the outer side of the first electrode 1541). Although not shown, the first electrode 1541 may be disposed in a compartment formed inside the cover 152 or coupled to the inside of the cover 152 by other alternative mechanisms. Another electrode (e.g., the second electrode 1542, which is a ring-shaped electrode) of the electric field generating unit 154 can be oppositely disposed in a ring-shaped compartment P1' (separated by the partition 156) near the sidewall of the housing 150. The power source 1543 of the electric field generating unit 154 may pass through a wiring opening (not shown) on the cover 152 via a wire to provide a voltage to the first electrode 1541 and the second electrode 1542. In still other alternative embodiments, second electrode 1542 may also be positioned outside of housing 150 by way of a support 155 (fig. 6, 8) extending from the outside of housing 150.

Some embodiments of the present disclosure also provide a filtering method 200, as shown in the flow chart of fig. 11. For illustration, the flow diagrams will be described in conjunction with fig. 1 and 4-10. First, the filtering method 200 includes operation 201: a fluid is passed through a filter element. In some embodiments, a fluid C (e.g., including water, photoresist, developer, etchant, slurry, process or cleaning gas, etc.) is passed through at least one filter device 15 (having a filter element 153, such as a porous membrane, disposed therein) to filter impurities (e.g., particles, metal ions or other foreign materials) therein that may affect or damage the process results of the semiconductor manufacturing tool 12 before being delivered to the semiconductor manufacturing tool 12 for semiconductor manufacturing use via a piping system 13.

Next, the filtering method 200 further includes an operation 202: an electric field is generated, so that impurities to be filtered in the fluid move to the filter element along the direction of the electric field. In some embodiments, an electric field generating unit 154 is provided, and an electric field E passing through the filter element 153 is generated by the electric field generating unit 154. The electric field E may be a direct current electric field, and the direction of the electric field may be non-parallel to the surface 153B of the filter element 153, for example, the direction of the electric field E and the surface 153B may form an angle α between 0 degrees and 180 degrees (but not including 0 degrees and 180 degrees). Alternatively, the electric field E may be an alternating electric field in which the direction of the electric field changes with time. The electric field E may be a continuous electric field or a discontinuous electric field, and is determined according to the characteristics (e.g., polarity, size, etc.) of the impurity X3 to be filtered in the fluid C. Under the action of the electric field E, the impurities X3 can move to the filter element 153 along the direction of the electric field E.

In addition, the filtering method 200 further includes an operation 203: the foregoing impurities are adsorbed by the filter element to filter the fluid. In some embodiments, the material of the filter element 153 may be modified to be a polar polymer (polar polymer) that does not contaminate the fluid C to be filtered, such as nylon or other similar structures, so as to adsorb (including "chemisorption" and "physisorption") the (polar or non-polar) impurity X3 that is directed to the filter element 153 by the electric field E. In addition, the filter element 153 also has a plurality of openings 153A for allowing the fluid C to flow through the filter element 153 and filtering impurities in the fluid C having a size larger than the plurality of openings 153A.

In summary, the embodiments of the present disclosure have the following advantages: the impurities to be filtered in the fluid can be actively driven to move to the filter element along the direction of the electric field by applying the electric field, so that the impurities are prevented from passing through the openings on the filter element along with the fluid under the condition that the impurities are not in contact with the filter element. Therefore, the capability of the filtering device for filtering impurities by using an adsorption mode can be improved. In addition, the intensity, frequency and mode of the applied electric field can be adjusted according to different characteristics of the impurities to be filtered, so that corresponding and enough electric field acting force can be generated to drive the impurities.

According to some embodiments, a filter device is provided, comprising a housing, a filter element, and an electric field generating unit. The housing has an inlet and an outlet, wherein the inlet allows a fluid to flow into the housing and the outlet allows the fluid to flow out of the housing. The filter element is arranged between the inlet and the outlet and is used for filtering impurities in the fluid flowing through the filter element in an adsorption mode. The electric field generating unit is configured to generate an electric field so that the impurities move to the filter element along the direction of the electric field.

According to some embodiments, the electric field generating unit includes a first electrode, a second electrode, and a power source for generating an electric field between the first electrode and the second electrode. The first electrode is disposed on one side of the filter element near the inlet, and the second electrode is disposed on the other side of the filter element near the outlet.

According to some embodiments, the first electrode and the second electrode are disposed outside the housing.

According to some embodiments, at least one of the first electrode and the second electrode is disposed in the housing.

According to some embodiments, the filter element further has a plurality of openings for allowing fluid to flow through the filter element and filtering impurities in the fluid having a size larger than the plurality of openings.

According to some embodiments, a filter device is provided that includes a housing, a filter element, an electric field generating unit, and an electrode mounting mechanism. The housing is configured to allow a fluid to flow in and out. The filter element is arranged on the flowing route of the fluid in the shell and is used for filtering impurities in the fluid in an adsorption mode. The electric field generating unit is configured to generate an electric field so that the impurities move to the filter element along the direction of the electric field, wherein the electric field generating unit comprises a first electrode, a second electrode, and a power source for generating the electric field between the first electrode and the second electrode. The electrode mounting mechanism is configured to mount the first electrode and the second electrode to the housing.

According to some embodiments, a method of filtering a fluid used in semiconductor manufacturing is provided that includes flowing a fluid through a filter element. The filtering method further comprises generating an electric field so that impurities in the fluid move onto the filter element along the direction of the electric field. Further, the filtering method includes adsorbing the aforementioned impurities by a filter element to filter the fluid.

According to some embodiments, the electric field is a dc electric field.

According to some embodiments, the direction of the direct current electric field is not parallel to the surface of the filter element.

According to some embodiments, the electric field is an alternating current electric field.

Although the embodiments and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. Furthermore, each claim constitutes a separate embodiment, and combinations of different claims and embodiments are within the scope of the disclosure.

Claims

1. A filtration device comprising:

a housing having an inlet and an outlet, the inlet allowing a fluid to flow into the housing and the outlet allowing the fluid to flow out of the housing;

a filter element disposed between the inlet and the outlet for filtering impurities in the fluid flowing through the filter element by an adsorption method; and

an electric field generating unit including a first electrode, a second electrode, and a power source for generating an electric field between the first electrode and the second electrode, wherein the electric field causes the impurities to move to the filter element along the direction of the electric field, wherein the fluid does not contact the first electrode and the second electrode of the electric field generating unit, and wherein the first electrode and the second electrode are disposed non-parallel to the filter element, so that an included angle is formed between the direction of the electric field generated by the electric field generating unit and the surface of the filter element, and the included angle is not 0 degree, 90 degrees, or 180 degrees.

2. The filter apparatus of claim 1, wherein the first electrode is disposed on one side of the filter element proximate to the inlet and the second electrode is disposed on the other side of the filter element proximate to the outlet.

3. The filter apparatus of claim 1, wherein the first electrode and the second electrode are disposed outside the housing.

4. The filter apparatus of claim 1, wherein at least one of the first electrode and the second electrode is disposed in the housing.

5. The filter apparatus of claim 1, wherein the filter element further has a plurality of openings for allowing the fluid to flow through the filter element and filtering impurities in the fluid having a size larger than the plurality of openings.

6. A filtration device comprising:

a housing configured to allow a fluid to flow in and out;

a filter element arranged on the flow path of the fluid in the shell and used for filtering impurities in the fluid in an adsorption mode;

an electric field generating unit configured to generate an electric field such that the plurality of impurities move to the filter element along a direction of the electric field, wherein the electric field generating unit includes a first electrode, a second electrode, and a power source for generating the electric field between the first electrode and the second electrode, wherein the first electrode and the second electrode are disposed non-parallel to the filter element such that an included angle is formed between the direction of the electric field generated by the electric field generating unit and a surface of the filter element, the included angle being different from 0 degree, 90 degrees, and 180 degrees; and

an electrode mounting mechanism configured to mount the first electrode and the second electrode to the housing without the first electrode and the second electrode contacting the fluid.

7. A method of filtering a fluid used in semiconductor manufacturing, comprising:

flowing the fluid through a filter element;

generating an electric field by an electric field generating unit, so that impurities in the fluid move to the filter element along the direction of the electric field, wherein the electric field generating unit comprises a first electrode, a second electrode and a power supply for generating the electric field between the first electrode and the second electrode, the first electrode and the second electrode are arranged to be not parallel to the filter element, so that an included angle is formed between the direction of the electric field generated by the electric field generating unit and the surface of the filter element, the included angle is not 0 degree, 90 degrees and 180 degrees, and the fluid cannot contact the first electrode and the second electrode of the electric field generating unit; and

the plurality of impurities are adsorbed by the filter element to filter the fluid.

8. The method of claim 7, wherein the electric field is a dc electric field.

9. The method of claim 7, wherein the electric field is an alternating current electric field.